In the manufacture of electronic/electrical components, it is typically needed to perform functional testing, such as Kelvin contact testing, on an electronic/electrical component to ensure that the device under test is in working condition and fulfils its specification.
An electrical component can be tested using a test apparatus, such as a contacting device, which typically comprises a mounting block for mounting the electrical component, and one or more electrical contacts such as contact fingers for contacting leads of the electrical component. To perform testing, the electrical component to be tested is positioned such that the leads of the electrical component establish electrical contact with the contact fingers of the contacting device.
Typically, two separate contact strips are provided in an electrical contact of the testing apparatus to contact one lead of the electrical component being tested in order to perform a Kelvin contact test. One contact strip is configured to provide a test signal while the other contact strip is configured to sense/receive signals. The contact strips are coupled to a processor unit which implements a test program and analyses the signals to obtain results of the test.
In order to achieve sufficient electrical contact, the lead of the electrical component should be positioned or to sit on both of the contact strips.
However, one problem that may arise is that due to the high speeds at which testing of multiple electrical components are carried out, an electrical component may be positionally offset such that a lead of the electrical component may be unable to maintain contact with both contact strips during testing. This may induce a Kelvin contact test failure and thus lower the overall test yield/productivity of the test apparatus.
Difficulties in proper positioning of the electrical components are further compounded by physical variations between electrical components. For example, mould offset may occur during the manufacturing stage, causing electrical components within a same batch to have slight physical variations and therefore, may not contact the electrical contacts of the test apparatus consistently.
To increase tolerance to positional offsets, it has been proposed that the contact strips be configured to include a L-shaped strip along one side of a straight strip. However, as discussed in WO 2011/141582A1, such a configuration is still not capable of establishing reliable electrical connection. For example, an electric component may be positionally offset such that a lead of the electric component sits on the opposite side of the straight strip from the L-shaped strip and not contacting the L-shaped contact strip.
To overcome the challenges associated with two separate contact strips, improvements have been proposed, such as to employ three or more separate contact strips per electrical contact to further increase the tolerance of the positional offsetting of electrical components. WO 2011/141582A1 discloses three contact strips being sequentially positioned such that at least two of the three contact strips establish an electrical connection with a lead of an electrical component. However, it has been recognised by the inventors that such an improvement increases fabrication cost and complexity due to the requirement for more strands of contact strips. The complexity also arises from fabrication and arrangement of three contact strips in relation to one another for each contact point and also the electrical wiring from various contact strips to the processor unit.
Thus, there exists a need for an electrical contact for contacting an electrical component that seek to address at least one of the above problems.